Well if you actually knew how much work goes into designing something, you wouldn't be saying that. I spend at minimum 10 hours on a design from research to planning it out etc.
Where are you getting this info from? $400 for a design is dirt cheap, Faction paid out $500 for their design contest plus a pair of skis. If indeed K2 pays their designers that poorly (which I highly doubt) I'm surprised K2 gets graphics to put on their skis year after year.
The average design cost for a T-shirt can be anywhere from 150 to 500 plus royalties, depending on company size and the production rate. For skis, especially big brands like K2 where they're producing skis numbering in the thousands, its totally fair to be charging $1500, 2000. I think other designers here will back me up on that. Again, it depends from work to work and I'm not saying that I would charge every company $2000 for a ski design, but I think what I said originally is fair.
I suggest you research a bit about what you post beforehand.